Recognition of the danger of electricity to persons in a work place having electrical equipment is certainly not new, but new emphasis has been placed on this danger, as well as steps to reduce risk, by regulations recently adopted by the Occupational Safety and Health Administration, U.S. Department of Labor. In 29 CFR Part 1910 are standards and procedures for reducing risks of injury to employees resulting from the unexpected energization or start-up of machines or equipment, or the release of stored energy. While the regulations are applicable to energy more broadly than just electrical energy, electricity is clearly one form of energy involved.
The regulations provide, in part, that employers are to have available lockout and tagout devices which can be used to reduce risks of electrical shock. One form of shock hazard relates to electrical cords or cables. For example, if a power cord is connected to a machine such that the machine is supplied with energy when a plug on the cord is inserted into a live receptacle, and if the machine is to be worked on, a prudent maintenance person would remove the plug from the receptacle before starting the work. However, it is possible for another person to restore the plug to the receptacle without realizing that the work is being performed, thereby subjecting the maintenance person to risk of shock. This is particularly applicable when the machine and the receptacle are not close to each other, or within sight of each other. The purpose of 29 CFR 1910 is to encourage the development and use of lockout devices which are designed to prevent such events, among others.
As will be apparent, a related source of serious physical injury can result from the unexpected start-up of machinery which has moving blades or activated presses, meshing gears or the like while the maintenance person is working on the machinery. While this does not involve electrical shock, the result is often no less serious.